SIP Proxy Edge Authentication for Header Security

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Solution Overview

Problem

Conventional SIP infrastructure is vulnerable to attacks and manipulation of SIP headers, and existing 3GPP IMS security solutions are complex, expensive, and ineffective in preventing such attacks, which compromises operator policies and user authentication.

Innovation Solution

A SIP proxy coupled with an access gateway performs initial authentication, forwards and modifies messages to ensure final authentication, and integrates with a P-CSCF to detect and prevent attacks by using IP address-based identity assertion, roaming partner identification, and quality of service management, thereby enhancing security and policy enforcement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional SIP infrastructure is used, then basic communication functionality is maintained, but the system is vulnerable to attacks and manipulation of SIP headers

Engineering Contradiction:
Improvesecurity of SIP infrastructureVSAvoidattacks and manipulation of SIP headers
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an edge proxy as an intermediary component between the access gateway and the core SIP infrastructure. This edge proxy acts as a mediator that receives SIP messages from mobile devices, performs security checks including authentication and header validation, and forwards legitimate messages to the P-CSCF. The intermediary prevents direct access to the core infrastructure, blocking attacks and header manipulation before they can reach vulnerable components.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The edge proxy performs preliminary security actions before messages reach the core SIP infrastructure. It conducts initial authentication with mobile devices, validates SIP headers, checks IP address-based identity assertions, and verifies roaming partner identification in advance. By performing these security checks preliminarily at the network edge, the system prevents malicious messages from progressing further into the infrastructure.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If existing 3GPP IMS security solutions are implemented, then security coverage is provided, but the system becomes complex and expensive

Engineering Contradiction:
Improvesecurity coverageVSAvoidcomplexity and cost of security measures
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the security functionality into a dedicated edge proxy component that operates independently at the network edge, separate from the core P-CSCF and other SIP infrastructure elements. This segmentation allows security functions (authentication, header validation, IP identity verification) to be isolated in a single component, reducing the complexity burden on the overall system while maintaining comprehensive security coverage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The edge proxy serves as a specialized intermediary that handles all security-related operations, freeing the core SIP infrastructure from complex security processing. By concentrating security functions in this intermediary component, the patent reduces the complexity and cost of security measures in the rest of the system while maintaining robust security coverage through the proxy's comprehensive validation capabilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If SIP headers can be manipulated, then flexibility in message customization is achieved, but operator policies are compromised

Engineering Contradiction:
Improvemessage customization flexibilityVSAvoidoperator policy enforcement
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The edge proxy implements feedback mechanisms by validating SIP headers against established operator policies before allowing messages to proceed. It checks IP address-based identity assertions, verifies roaming partner identification, and ensures that message customization does not violate policy constraints. The proxy provides feedback by blocking messages that fail policy validation while allowing compliant customized messages to pass through, thus maintaining both flexibility and policy enforcement.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The edge proxy as an intermediary enforces operator policies by inspecting and validating SIP headers and message content before forwarding to the core infrastructure. It acts as a policy enforcement point that allows legitimate message customization while blocking manipulations that would compromise operator policies, thus reconciling flexibility with reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2135181B1Gw coupled sip proxy
Publication Date: 2018.06.06 CISCO TECHNOLOGY INC
  • EP2135181B1 patent drawingFigure 1
  • EP2135181B1 patent drawingFigure 2
  • EP2135181B1 patent drawingFigure 3

AI summary

In one embodiment, a method can include: (i) performing an initial authentication with a mobile device in an access gateway, the access gateway being a point of attachment; (ii) forwarding a first message from the mobile device to an edge proxy; (iii) receiving a second message from the edge proxy; and (iv) returning a modified version of the second message to the edge proxy for a final authentication of the mobile device.